1. Field of the Invention
This invention relates generally to apparatuses for providing convective heat transport; and, more particularly to apparatuses such as heat sinks, cold plates, and heat exchangers including arrays of pin-shaped fins for use in removing heat generated in, e.g., electronic systems and components, and methods of manufacturing such pin fin arrays.
2. Background
Traditionally, apparatuses such as heat sinks, cold plates, and heat exchangers including plate-shaped fins have been used for removing or transferring heat generated in, e.g., electronic components and systems during operation. More recently, heat sinks, cold plates, and/or heat exchangers with arrays of elongated, pin-shaped fins (also known as "pin fin arrays") have been used for similar purposes.
Many different types, geometries, and styles of fins included in pin fin arrays have been contrived including, e.g., circular and rectangular cylinders, conical protrusions, serrated extrusions, and fluted cylinders. The term, pin (as used in "pin fin array"), is a vestige from early designs in which wire pins were used to create the array, and is generally used in contemporary pin fin array designs to refer to any fin configuration, some of which are mentioned above. Further, the phrase, pin fin array, is generally used to refer to any cold plate, heat sink, or heat exchange surface that uses an array of structures (of a variety of geometries and/or configurations) for inducing turbulence and increasing wetted surface area for the purpose of enhancing heat transfer from (or to) the array to (or from) a fluid medium by convective heat transport.
Pin fin arrays have advantages over plate-shaped fins in that they typically provide a larger surface area over which the generated heat can be absorbed or dissipated, and are generally better suited for applications in which coolant flow characteristics are unknown or variable in magnitude and/or direction. Such pin fin arrays have therefore been used for significantly improving heat transfer and thermal control in, e.g., highly integrated and/or power dense electronic components and systems.
One example of heat sinks having pin-shaped fins, including a process for producing the heat sinks, is disclosed in U.S. Pat. No. 5,421,406 ("the '406 patent") issued Jun. 6, 1995, to Furusawa et al. In accordance with that disclosure, such heat sinks include a heat dissipating base plate, and a plurality of comb-like fin members arranged in parallel at a predetermined spacing on one surface of the base plate approximately perpendicular thereto. Each of the fin members include pin-shaped fins arranged in a row and a connector that connects the fins together each at one end thereof, the connector of each fin member being joined to the surface of the base plate. The fins are given a greater height and arranged with a reduced pitch with a higher density for disposal of increased amounts of heat. To prepare the heat sink, the fin members are blanked out from a metal sheet; the fin members and spacer plates are arranged alternately on one surface of a heat dissipating base plate approximately perpendicular thereto; the connectors of the fin members are joined to the base plate; and, the spacer plates are thereafter removed. A comb-like fin member having pin-shaped fins and a large length is bent to a zigzag form when seen from above.
However, the heat sinks described in the '406 patent have some drawbacks. For example, the plurality of comb-like fin members is arranged on the surface of the base plate in such a way that the fins of each fin member are in-line with the fins of adjacent fin members. Such an arrangement of fin members often results in heat sinks with less-than-optimal heat transfer characteristics. Further, the process for manufacturing the heat sinks includes the steps of alternately arranging the fin members and the spacer plates on the surface of the base plate, joining the connectors of the fin members to the base plate, and then removing the spacer plates. However, such use of spacer plates in the production of heat sinks with pin-shaped fins frequently leads to complicated manufacturing processes that can significantly increase the cost of the heat sinks.
Another example of heat sinks with pluralities of fin segments is disclosed in CA Patent 1,026,013 ("the '013 patent") issued Feb. 7, 1978, to Elgar et al. In accordance with that disclosure, a heat sink for a semiconductor cell includes a predetermined length cut from an aluminum extrusion. The length of the extrusion has a body portion adapted for heat conducting contact with the semiconductor and a number of fins projecting from the body portion in spaced relation, defining fluid flow passages between fins. Further, a device for transferring heat from the sink to the fluid includes slits across some or all of the fins, thereby dividing these fins into fin segments. At least some of the fin segments are offset into adjacent flow passages for increasing turbulence of fluid flow and fin surface, thereby increasing heat transfer from the sink to the fluid.
Although the heat sinks described in the '013 patent have improved heat transfer characteristics, these heat sinks also have some drawbacks. For example, the process for manufacturing the heat sinks includes the step of forming a heat sink with fin segments from an aluminum extrusion. However, in order to produce heat sinks with high fin segment densities from such extrusions, it is often necessary for the heat sinks to undergo a post-machining process, which can also significantly increase the cost of the heat sinks.
Other processes for manufacturing pin fin arrays include mold casting; and, cold, warm, or hot forging. However, pin fin arrays produced using mold casting must also generally undergo post-machining processes, which typically increase costs. Similarly, processes for manufacturing pin fin arrays by forging are frequently expensive. Moreover, pin fin arrays produced using these manufacturing processes often do not have the densities and/or configurations required for optimally controlling heat transfer in today's highly integrated and/or power dense electronic components and systems.
It would therefore be desirable to have an improved pin fin array for providing optimal thermal control in highly integrated and/or power dense electronic components and systems. Such pin fin arrays would have fin densities and configurations for improving heat transfer from the pin fin arrays to a coolant. It would also be desirable to have a process for manufacturing such pin fin arrays that is both simple and low-cost. Such a manufacturing process would also provide increased flexibility, thereby allowing the design and optimization of pin fin arrays suitable for use with a wide range of systems and components having a wide range of performance requirements.